www.iiece.org GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
ISSN:- 2349–283X
COMPARITIVE STUDY OF THE PROPERTIES OF FLY ASH CLAY BRICKS AND CLAY BRICKS 1Ramji
Porwal Department of Civil Engineering, Madan Mohan Malviya University of Technology, Gorakhpur, India Email: ramporwal123@gmail.com Abstract: Brick is one of the most widely used construction materials throughout the world since ancient time. Fly ash clay bricks are one of the best alternatives to the conventional burnt clay bricks. This dissertation gives the results of an experimental investigation in which the compressive strength, water absorption, density and durability of Fly ash-clay bricks are investigated by using varying quantities of fly ash with partial replacement of clay. The properties of Fly ash clay bricks are compared with those of the ordinary burnt clay bricks. The results indicate that these bricks are lighter in weight, durable in aggressive environments and have sufficient strength for their use in building construction. Keywords: Fly ash; Brick; Clay; Sand; Compressive Strength. 1. GENERAL- .Fly Ash from the NTPC TANDA
In India, construction industry shares a part about
(U.P.) plant produces 6-800 tons of fly ash per day,
9 % of the Gross Domestic Product (GDP), and
over 20 MT a year, in the form of dry Bottom Ash.
annual growth of about 10%. Clay bricks are the
Gorakhpur is situated only 111 km away from the
main building material for the construction
NTPC Tanda, Ambedkar Nagar (U.P.). Energy
industry and housing. In developing countries in
requirements for the countries for electricity get
the world, India is one of the largest with the
energy from coal. Thermal power stations use
economic growth rate averaging 9% for the last 5
pulverized coal as fuel generates large quantities
years plan so that this growth rate will also effect
of fly ash as by-product. The disposal of the
on the construction work and GDP. The brick
thermal waste is called fly ash. Fly ash is a
technology in India varies from region to region
powdery substance collected by the electrostatic
and depends generally on scale of production, soil
precipitators in the thermal power plants. There
and fuel available, demand, market conditions and
are about 125 thermal power plants in India,
also on the enforcement of law for shifting from
which form the major source of fly ash in the
one
technology
to
the
other
country (Kumar and Singh, 2006).
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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
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Share in world brick production
11% 23%
India China Bangladesh
8%
Pakistan 4%
other Countries
54%
Fig 1 Share in world brick production The GOI (Government of India) on 14th September
elongated shape. Their specific surface is infinitely
1999, published in the Gazette under S.O. 763 (E),
greater than that of rougher round or angular
Directions under the Environment (Protection)
particles. Clay is one of the most mineral materials
Rules, notifying the “Use of fly ash, bottom ash
on all over the earth for bricks.
or pond ash in the manufacture of bricks and other construction activities.” (Annex 14). It requires brick-makers within a radius of 50 KM from thermal coal or lignite-based power plants to use at least 25% by weight of ash to
Clays occur in three principal forms, all of which have similar chemical compositions but different physical characteristics. 1.
Surface Clays- Surface clays may be the up thrusts of older deposits or of more recent
be mixed with soil for brick-making.
sedimentary formations. As the name implies,
2. RAW MATERIALS- The raw materials which
they are found near the surface of the earth.
are used for the making of bricks are as follows2.
Shale- Shale is clays that have been subjected
(i) Clay- Clay is a fine grained soil. It is a cohesive
to high pressures until they have nearly
soil. The particle size is less than 0.002 mm. It is
hardened into slate.
usually dark grey or black in colour. It is
3.
Fire Clays- Fire clays are usually mined at
conspicuous odour. They differ from other grains
deeper levels than other clays and have
in their chemical composition and physical
refractory qualities.
properties. In chemical terms they are hydrated
(ii) Fly Ash- A fine glass powder recovered from
alumina-silicates formed by the leaching process
the gases of burning coal during the production of
acting on the primary minerals in rock. Physically
electricity is fly ash. These micron sized earth
speaking, clay very often assumes a platy
elements consist primarily of silica, alumina and
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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
ISSN:- 2349–283X
iron. The combustion of powdered coal in thermal
These micron sized earth elements consist
power plants produces fly ash. The high
primarily of silica, alumina and iron. The
temperature of burning coal turns the clay
combustion of powdered coal in thermal power
minerals present in the coal powder into fused
plants produces fly ash. The high temperature of
fine particles mainly comprising of aluminum
burning coal turns the clay minerals present in the
silicate. Fly ash produced thus possesses both
coal powder into fused fine particles mainly
ceramic and pozolanic properties. A fine glass
comprising of aluminum silicate. Fly ash produced
powder recovered from the gases of burning coal
thus possesses both ceramic and pozolanic
during the production of electricity is fly ash.
properties.
Table 1: Physical Properties of Fly Ash Sl. No.
Constituent/Property
Value
1
Colour
Grey
2
Percent passing 75µ sieve
76%
3
Size of particle
0.002-0.30mm
4
Maximum Dry Density (MDD)
1.183g/cc
5
Optimum Moisture Content
22%
6
Specific Gravity
2.02 at 270C
8
Plastic Limit
Non-plastic
9
Classification
Class C and Class F
3. METHODOLOGY OF MAKING BRICKS-
5) Drying of Bricks.
Clay fly ash brick manufacturing is most suitable for transition with minimum changes from existing practices and manual molding of bricks, which is most common. CBRI technology is well tried and tested. These can also have semimechanized operations, but manual operations are most effective cost. There are many processes which are used for the manufacturing of Bricks. The major steps in preparation of bricks by Chimney Kilns process are as follows:1) Collection of Different clay and Fly ash. 2) Mixing and preparation of clay-fly ash mix.
6) Filling of Kiln. 7) Burning of kiln. 8) Inspection and sorting of Bricks according to grades. Fly
Ash-Clay
Brick:
(As
per
CBRI)
Brick
Composition: Fly Ash - 30% and Clay- 70%.We have taken five samples of clay and fly ash i.e. 1) Clay- 75% and Fly Ash -25% 2) Clay- 70% and Fly Ash -30% 3) Clay- 65% and Fly Ash -35% 4) Clay- 60% and Fly Ash -40% 5) Clay- 55% and Fly Ash -45%
3) Preparation of Bricks through moulds. 4) Moulding Procedure
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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
Fly Ash
ISSN:- 2349–283X
Clay
Proportion of Fly Ash & Clay
Dry Mixing & Pulverization
Water
Wet Mixing
Moulding of Bricks
Sun Drying
Setting the Bricks in kiln for firing for 14 days da Cooling for 3-4 days
Testing the Bricks for WA & CS
Analysis of Results Fig 5.8 Flow chart showing methodology of bricks
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4. EXPERIMENTAL SET UP & PROCEDURE-
from
bricks
stack.
Any
blister,
small
Tests are conducted for the acceptance of bricks
projections or loose particles of clay that adhered
for building construction. We have to be very sure
to each brick are removed.
about strength and worthiness of basic building unit i.e. Bricks. Following tests are performed to check the quality of bricks4.1. DIMENSION AND TOLERANCE TESTFor the bricks dimensions measurement, the procedures
is
based
on
Clause
5.2.1,
IS
12894:2002. The required apparatus in this test is measuring tape. The number of specimens for the test shall be selected according to IS 5454:1976. In this test, a total of 10 bricks are selected randomly Table 2: Size of bricks SIZE OF BRICK
LENGTH (mm) 230
WIDTH
HEIGHT
(mm)
(mm)
120
75
PLAN AREA (mm2) 27600
4.2 WATER ABSORPTION TEST
is absorbed. The total water absorption is defined
The Bricks are weighed dry. Then they are
as the increase in the weight of a material due to
immersed in water for a period of 24 hours.
moisture in air, and procedure is as follows-
Samples are taken out and wiped with cloth. The Water absorption in (%) =
weight of samples in wet condition is determined.
× 100%
The differences in weights indicate that the water Sl. No.
% OF FLY ASH ADDED
1
25
14.785
14.774
14.919
14.457
14.822
14.751
2
30
18.857
17.575
18.329
17.441
17.106
17.861
3
35
16.636
16.961
17.047
16.949
17.366
16.991
4
40
17.909
17.495
17.780
17.523
17.988
17.154
5
45
16.566
17.091
17.047
17.338
17.731
17.739
Sl. No.
WATER ABSORPTION (%) SA-1
SA-2
SA-3
SA-4
SA-5
AVERAGE
WATER ABSORPTION OF CLAY BRICKS (%) SA-1
SA-2
SA-3
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SA-4
SA-5
AVERAGE
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N1
14.571
12.527
13.812
13.295
12.484
13.337
N2
14.976
14.785
14.042
13.426
14.085
14.262
N3
14.746
15.079
12.305
14.542
13.469
14.028
N4
14.961
14.774
12.416
14.263
13.787
14.032
N5
15.152
13.888
14.944
14.065
14.960
14.601
4.3 COMPRESSIVE STRENGTH TEST
compressive strength the following dimensions
The Test is conducted as per IS-3495, Part-1,
are taking as average dimension. The calculation
1992. The load is applied axially at a uniform rate
for the compressive strength of bricks is as:
of 15 N/mm2. The crushing load is noted as IS an (Indian Standard) code permitting the limits for
Compressive Strength =
the good quality bricks. Calculation of the COMPRESSIVE STRENGTH OF CLAY BRICKS(N/mm2)
Sl. No.
SA-1
SA-2
SA-3
SA-4
SA-5
AVERAGE
N1
9.601
9.782
9.420
9.239
9.420
9.420
N2
9.963
9.601
9.782
9.963
9.963
9.601
N3
10.14
10.32
9.963
9.782
9.420
9.420
N4
9.420
9.601
9.782
9.963
10.50
10.32
N5
9.601
9.239
9.420
9.420
9.420
9.782
Sl. No.
% OF FLY ASH ADDED
COMPRESSIVE STRENGTH OF FLY ASH CLAY BRICKS (N/mm2) SA-1
SA-2
SA-3
SA-4
SA-5
AVERAGE
A
25
6.34
6.15
6.08
6.34
6.88
6.35
B
30
6.70
7.06
6.34
7.24
7.42
6.95
C
35
8.69
8.51
9.23
8.87
9.42
8.94
D
40
5.61
7.24
6.15
6.08
5.43
6.10
E
45
5.97
5.79
5.61
5.97
5.79
5.82
4.4 EFFLORESCENCE TEST
immersed in water for 24h. It is then taken out
In bricks presence of the soluble salts cause
and allowed to dry in shade. The absence of grey
efflorescence on the surface of brick. Brick is
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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
ISSN:- 2349–283X
or white deposits on its surface indicates absence
observations are made from fly ash clay bricks
of soluble salts.
with different percentage of fly ash and also
Observation is made with naked eyes and
minimize impacts on the environmental by
classified as below.
utilization of Class F fly ash in the manufacturing
Nil
–
No
patches
or
imperceptible
of bricks .The present research replicate the effect
efflorescence.
of waste product like Fly Ash on compressive
Slight – 10% of area covered with deposits.
strength of brick and results is obtained. The
Moderate – 10 to 50% area covered with
results of Fly Ash Clay Bricks and Clay Bricks are
deposit but unaccompanied by flaking of the
as per IS-1077 – 1992 and IS-13757 – 1993
surface.
respectively. From the experimental results
Heavy – More than 50 per cent area covered
obtained, it can be concluded that
with deposits but unaccompanied by flaking
1) The burnt bricks manufactured with fly ash
of the surface.
appearance when compared to the clay bricks, the
Serious – Heavy deposits of salt accompanied
percentage of water absorption for bricks is found
by flaking of the surface
to be less than that of conventional bricks but still
5. RESULTS AND CONCLUSION-
within the prescribed maximum limit as per
After all the efforts and learning of local
Indian Standards maximum is 20%. The Clay
technologies and practices and with the help of
burnt bricks, when tested in accordance with the
experimental
procedure
investigation,
the
following
20 18
WATER ABSORPTION ( % )
16 14 12 10 8 6 4 2 0
A
N1
B
N2
C
N3
D
N4
E
N5
FLY ASH CLAY BRICKS
14.751
17.861
16.991
17.154
17.739
CLAY BRICKS
13.337
14.262
14.028
14.032
14.601
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2) The Clay bricks having fly ash as an admixture
conclude that compressive strength of Fly Ash
showed
Clay bricks is good than the clay bricks. We can
the
best
performance,
having
a
compressive strength of near about conventional
use it for future work as a building material.
bricks. In this figure the compressive strength of Fly Ash Clay Bricks is similar to the Clay Bricks against the 35% fly ash added. Hence we can
COMPRESSIVE STRENGTH (N/mm2)
12
10
8
6
4
2
0 A
N1
B
N2
C
N3
D
N4
E
N5
SAMPLE OF BRICKS 3) Finally it can be concluded from the above experiments, the properties of the fly ash clay burnt bricks which are as given belowOptimum % of fly ash addition
35%
Water Absorption (at 35% Fly Ash)
17 %
Compressive Strength (at 35% Fly Ash):
8.94 N/mm2
The properties of clay bricks are as followsWater Absorption
14.6 %
Compressive Strength
10.32N/mm2
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Hence the bricks may be termed as Class 7.5 as per BIS: 3492 Part 2: 1992 and the Class 10 as IS 13757:1993, the water absorption up to class 12.5 should be less than 20% as per IS 3495 (Part 2): 1992. The bricks prepared confirm to this criterion too Sl.
CLAY BRICKS
FLY ASH CLAY BRICKS
1
Varying colour as per soil
Uniform pleasing colour like cement
2
Uneven shape as hand made
Uniform in shape and smooth in finish
3
Lightly bonded
Dense composition
4
Plastering required
No plastering required
5
Heavier in weight
Lighter in weight
6
Compressive strength is around 10.02N/mm2
Compressive strength is around 8.94 N/mm2
7
More porous
Less porous
No.
CONCLUSIONS-
buildings as well as houses and also no
1) Thermal conductivity Of Fly Ash Bricks is
breakage during transport use.
0.90-1.05
W/m2
ºC
while
thermal
3) Fly ash clay bricks have less porous, absorbs
conductivity Of Normal Clay Bricks is 1.25 –
very little water, whereas burnt clay bricks
1.35 W/m2 ºC so FACB (fly ash clay bricks)
absorbs more water during construction.
absorbs less heat than normal bricks, it keeps
Sprinkling of water before use is enough.
your building cool even in summer, hence
Saves money on water during construction
most suitable for Indian conditions.
and even keeps your building strong during
2) Fly ash bricks are light weight bricks
rainy seasons.
compared to clay bricks. These are 25%
4) Fly ash clay bricks are high quality bricks and
lighter than the clay bricks, so it is suitable for
do not have the cracks on its surface. Surface
multi storey building. Less weight means less
is neat and clean and plaster (Plaster of Paris)
stress on the building, safety assured. These
can be directly applied on these bricks
bricks will reduce the structural load and also
without a backing coat of lime.
reduce the construction cost. Hence these
5) Clay
bricks are suitable for the construction of
can
be
used
as
a
chemical
accelerator/binder for Fly ash clay bricks as fly ash is non-plastic. Fly ash clay bricks are
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GJESR RESEARCH PAPER VOL. 1 [ISSUE 10] NOVEMBER, 2014
ISSN:- 2349–283X
cheaper than ordinary “First class Clay Brick”
[3] Indian Standard, Guidelines For Utilisation
and cost effective in use and environment
and Disposal of Fly Ash, IS: 10153 - 1982,
friendly. Fly ash clay bricks result in
Indian Standards Institution, New Delhi
efflorescence is less or negligible.
[4] O. Kayali, “High performance bricks from fly
6) Clay which is used for manufacturing of clay
ash”, Proceedings of the World of Coal Ash
bricks so need for conservation of natural
Conference, Lexington, Kentucky, 2005.
resources. By consuming 80-82% fly ash, the
[5] Chou Mie-In (2002), “Fired Bricks from Fly
cause of environmental pollution and hazards
Ash”, A Report Published by the Illinois State
due to disposal is minimized.
Geological Survey, a Division of the Illinois, Department of Natural Resources, 615 East
REFERENCES-
Peabody Drive Champaign, IL 61820-6964, USA, 2002
[1] Kumar, V. (2006): “Fly ash: A resource for sustainable
development’,
Proc.
of
[6] Nirvan G. (2008), “It’s Time to Go in for Green
the
Bricks
International Coal Congress & Expo, 191-199.
Strength Materials
of to
Bricks
Made
Clay
Bricks.”,
With
PrachaR
–
Integrated
Communications Consultant, The Hindu, On-
[2] Aashish Kumar Parashar, Rinku Parashar (2012), “Comparative Study on compressive
now”,
line Edition, September 6th, 2008. [7] ASTM E 1861 (1997) “Standard guide for the
Various
International
use of coal combustion by products in structural fills.” Philadelphina, U.S.A.
Journal of Science and Research Publication, Volume 2, Issue 7, July.
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